(USA Today) -- Younger buyers are increasingly choosing Detroit brands over Japanese rivals, a huge reversal from the past, reports research groups R.L. Polk and Edmunds.com.

New vehicles from Detroit's Big 3 -- General Motors, Ford Motor and Chrysler -- accounted for 36.8% of cars bought by Americans age 25 to 34 in 2012, up from 35.4% in 2008. During the same period, the share of cars from Japanese brands -- Toyota, Nissan, Honda and others -- for the same age group fell from 50.6% to 42.9% during the same period.

Detroit automakers have reached out to young buyers as never before with a raft of appealing small cars that they would have rejected as unprofitable in the past. Chrysler Group has the fun Fiat 500, General Motors has models like the small Chevrolet Sonic and smaller Spark and Ford has sponsored TV's American Idol for its small car lineup, like the Fiesta and Focus..

But before anyone breaks out the champagne in Detroit, there's another factor to consider: Hyundai. The same Edmunds study based on Polk data found that many buyers fleeing Japanese brands looked to the Hyundai or Kia.

Young buyers snapped up about 10% made by the twin South Korean brands, a rate that has doubled since 2008, according to the study.

"U.S. automakers have burst onto the scene in recent years with small, fuel-efficient and affordable cars that really appeal to a young set of buyers," says Edmunds.com senionalyst Jessica Caldwell in a statement. "But while Detroit might be chiseling away at the Japanese grip on Gen X and Gen Y, South Korean brands are taking big hacks."

She says in addition to an appealing lineup of cars for younger buyers, Hyundai and Kia also have made credit available to young buyers who may have limited work histories.